Many important assays involve the use of labile reagents, such as peptides, enzymes, antibodies, or other compounds that are readily degraded outside narrow environmental ranges. Such assays include enzyme-based nucleic acid amplification assays, immunoassays, enzyme substrate assays, and the like. The sensitivity of these reagents not only makes routine handling and transport more difficult, but also often limits the application of such assays outside of research settings, since opportunities are not available to provide fresh reagents or to monitor the properties or activities of the reagents. These are significant limitations in view of the great interest in using these assays for a host of important monitoring tasks, frequently in outdoor settings, where transport, environmental control, and ready access to instrumentation used with the assays may be limited or unavailable. Examples of such monitoring applications include bio-defense monitoring, agricultural and livestock monitoring, pathogen testing, acute care medical applications, and the like.
Some problems related to the lability of protein assay reagents have been addressed by lyophilization, or freeze-drying, e.g. Franks et al, U.S. Pat. No. 5,098,893; Cole, U.S. Pat. No. 5,102,788; Shen et al, U.S. Pat. No. 5,556,771; Treml et al, U.S. Pat. No. 5,763,157; De Rosier et al, U.S. Pat. No. 6,294,365; Buhl et al, U.S. Pat. No. 5,413,732; and the like. However, when freeze-dried reagents are used as powders or other small particulates, difficulties can arise in controlling their disposition in containers or reaction chambers because of static charges carried by the particulates, e.g. Matsusaka et al (2002), Advanced Powder Technol., 13: 157-166. This is particularly troublesome in disposable plastic or solid polymer cartridges that are pre-loaded with such particulates or powders and can easily lead to cartridge-to-cartridge measurement variability because the lyophilized particulates become inappropriately dispersed and are not rehydrated completely.
It would be useful if reagent storage components or cartridges were available that could be pre-loaded with lyophilized particulates, or like materials, and that would permit complete re-hydration of reagents in desired concentrations and amounts with minimum possibility of being dispersed to areas out of contact with a re-hydrating or activating solution.